CN115745526A - Coal mine filling material and preparation process thereof - Google Patents
Coal mine filling material and preparation process thereof Download PDFInfo
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- CN115745526A CN115745526A CN202211668691.3A CN202211668691A CN115745526A CN 115745526 A CN115745526 A CN 115745526A CN 202211668691 A CN202211668691 A CN 202211668691A CN 115745526 A CN115745526 A CN 115745526A
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Abstract
The invention discloses a coal mine filling material, which relates to the technical field of mine filling materials and is prepared from the following raw materials in parts by weight: 20-25 parts of fly ash, 40-45 parts of cement, 5-8 parts of construction waste, 15-18 parts of coal gangue, 2-3 parts of composite fiber, 3-4 parts of additive, 0.8-1.0 part of expanding agent, 5-6 parts of styrene-acrylic emulsion, 0.6-0.7 part of foam stabilizer and 100 parts of water. The additive and the expanding agent are added into the filling material, the expansion rate of the filling material can reach 16-22%, the compressive strength is 3.4-4.8MPa, and the requirements of filling roof and strength can be met.
Description
Technical Field
The invention relates to the technical field of mine filling materials, in particular to a coal mine filling material and a preparation process thereof.
Background
In recent years, the specific gravity of coal consumption tends to decrease, but coal energy remains as our main energy source. On one hand, a large-scale goaf is formed in the coal mining process, and the surface subsidence is easily caused; on the other hand, in the process of coal mining and roadway excavation, the situations of rock stratum crushing, water leakage and the like are easy to occur, and potential safety hazards exist. Among the technologies for preventing surface collapse and improving the environment of a mining area, the filling technology is most widely applied.
The filling technology is characterized in that artificially formed filling materials are conveyed to a coal mine goaf or an area needing to be reinforced, and a filling body is formed after solidification, so that the effect of reinforcing and supporting is achieved, not only can surrounding rocks be supported, but also the damage or movement of the surrounding rocks in the goaf can be delayed or reduced, and therefore the filling technology is used for controlling the collapse or surface subsidence of the surrounding rocks and ensuring safe production. The currently common filling materials comprise water sand filling, paste filling, polymer grouting materials and the like, wherein the main components of the paste filling materials comprise coal gangue, fly ash, municipal construction waste, slag and the like, then loess, gravel and gel materials are added into the paste filling materials to be mixed into paste-shaped slurry, and the paste-shaped slurry is conveyed to a goaf through a pipeline by adopting a filling pump or self weight. Polymer grouting materials such as epoxy resin grouting materials, polyurethane grouting materials, and the like.
The problems of the existing filling technology and filling material are that: 1. bleeding and sinking, in order to ensure transportation, the slurry concentration is low, and the slurry is separated and excessive water flows out after filling, so that sinking and shrinking are caused; in addition, the filling material can sink in the curing process, so that the filling body cannot be abutted; 2. in order to solve this problem, it has been attempted to fill the filler with a foam material, but the use of a foam material requires consideration of whether the strength of the filler can meet the requirements.
Disclosure of Invention
In view of the above, the invention aims to provide a coal mine filling material aiming at the defects of the prior art, wherein an additive and an expanding agent are added into the filling material, the expansion rate of the filling material can reach 16-22%, the compressive strength is 3.4-4.8MPa, and the requirements of filling roof and strength can be met.
In order to achieve the purpose, the invention adopts the following technical scheme:
the coal mine filling material is prepared from the following raw materials in parts by weight: 20-25 parts of fly ash, 40-45 parts of cement, 5-8 parts of construction waste, 15-18 parts of coal gangue, 2-3 parts of composite fiber, 3-4 parts of additive, 0.8-1.0 part of expanding agent, 5-6 parts of styrene-acrylic emulsion, 0.6-0.7 part of foam stabilizer and 100 parts of water.
Further, the construction waste is subjected to activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and is kept warm for 60min.
Further, the additive is prepared by the following steps:
(1) Crushing the dried straws, soaking for 3 hours at 50 ℃ by adopting 9-10% alkali liquor by mass percent, wherein the solid-liquid ratio is 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw, stirring for 30-40min at room temperature 2 Adding potassium persulfate into the atmosphere at 70 ℃ to initiate reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuing to react for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of the acrylic acid, the 2-acrylamide-2-methylpropanesulfonic acid, the alkalized straw, the sodium carboxymethyl cellulose, the hectorite, the sodium dodecyl sulfate, the N, N-methylene bisacrylamide, the polyethylene glycol diacrylate, the potassium persulfate and the water is 36:9:1:2:3.5-4.5:0.3:0.025:0.015:0.35:100.
further, the swelling agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, mixing the mixture with a proper amount of absolute ethyl alcohol uniformly, adding calcium carbide, performing ultrasonic oscillation for 1 hour, and evaporating the absolute ethyl alcohol to obtain coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is (3-4): 100, respectively;
(2) Soaking expanded vermiculite in 1.5-2 mol/L hydrochloric acid for 24 h, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the film-coated calcium carbide and aluminum powder according to a weight ratio of 2:0.5:0.5-1, and evenly stirring to obtain the expanding agent.
Furthermore, the composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and the length of the composite fiber is 5-6mm.
Further, the foam stabilizer comprises the following components: 10-15 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 10-15 parts of methyl glucoside polyoxyethylene ether dioleate, 2-5 parts of hexadecyl trimethyl ammonium bromide and 2-3 parts of nano calcium carbonate.
A preparation process of a coal mine filling material comprises the following steps:
uniformly mixing the fly ash, the cement, the building waste and the coal gangue, adding the composite fiber, and further uniformly stirring; then adding the rest raw materials, stirring uniformly, and conveying to the area to be filled by pressurizing through a pipeline pump.
The beneficial effects of the invention are:
1. the coal mine filling material with the expansion performance is prepared by solving the problem that a coal mine filling body cannot be connected with a roof in the prior art, cementing components, aggregates and fibers are used as raw materials, and a high-molecular emulsion, an additional water-retaining expansion agent and a foaming agent are added, so that the prepared slurry is good in fluidity, has a certain expansion performance, and is high in strength and good in toughness.
2. The cementing components are fly ash and cement, the aggregate is construction waste and coal gangue, the cost can be further reduced, the construction waste is activated, the activity is increased, and the particle size is smaller than 1mm; the grain diameter of the coal gangue is 1-6mm, wherein the grain diameters of 1-2.5mm, 2.5-4.5mm and 4.5-6mm respectively account for 50%, 25% and 25%, and the grain diameter grading is helpful for increasing the skeleton bulk density and improving the strength of the filling body. The prepared expansion filling body is added with the composite fiber and the styrene-acrylic emulsion for reducing cracks in the expansion hardening process and increasing the toughness and the strength, so that the composite fiber can form a net structure in the filling body and can inhibit and delay the generation of the cracks of the filling body; the active group in the styrene-acrylic emulsion can combine with calcium, silicon and other ions in the slurry to form a new chemical bond, so that the crosslinking density of the ettringite and the C-S-H gel is increased, and the mechanical property of the filling body is increased.
3. The additive and the expanding agent are added, wherein the additive is high in water absorption, can compensate water in the cement hydration expansion process, delays cement shrinkage, and improves the crack resistance, carbonization resistance and mechanical property of the filling body.
Because the slurry needs pipeline transportation, the water absorption expansion of the admixture is delayed, and the fluency of pipeline transportation can be ensured; the admixture of the present application is prepared by solution polymerization methodThe sodium carboxymethylcellulose and the straws are used as substrates, the corn straw fibers are long, good in toughness, wide in source and degradable, and are economical and environment-friendly as raw materials for preparing the water-retaining agent, and the straws are subjected to alkalization treatment firstly, so that the grafting reaction with other components is facilitated; inorganic filler hectorite is also added, the hydrophilicity is strong, the surface contains a large number of hydroxyl groups, the sodium carboxymethylcellulose and the monomer are subjected to graft reaction under the action of an initiator and a cross-linking agent, and in addition, the hydroxyl groups on the straw and the hectorite can be subjected to COO on the monomer - Reacting to form a cross-linked network structure, and having strong water-absorbing swelling property and water-retaining property.
And a small amount of sodium dodecyl sulfate can increase the gaps of a gel network so as to improve the water absorption performance. The admixture adopts two crosslinking agents, the crosslinking agents can limit the swelling degree in the process of water absorption and swelling, and the polyethylene glycol diacrylate is also continuously hydrolyzed and broken in the cement hydration process, so that the water-retaining particles are further swelled, and the swelling speed can be slowed down.
4. The expanding agent in the application is compounded by adopting aluminum powder and calcium carbide, and the aluminum powder can generate hydrogen in the cement hydration process, so that a matrix is expanded, but the reducibility is small, and the reaction degree is lower; the calcium carbide can rapidly generate acetylene gas when meeting water, and the reaction speed and the gas generation speed are high, so that a large number of air holes can be formed in the hydrated slurry, but the gas is inflammable and cannot be used in a large amount, and the calcium carbide and aluminum powder are compounded to be used as a foaming agent.
Because calcium carbide reacts with water, the calcium carbide is coated on the surface of the calcium carbide, then is mixed with aluminum powder and then is fully mixed with the acidified expanded vermiculite, the specific surface area of the acidified expanded vermiculite is further increased, the aluminum powder and the coated calcium carbide can be adsorbed in the porous structure of the acidified vermiculite, and the foaming time of the foaming agent can be delayed; after the acidified expanded vermiculite absorbs water, the aluminum powder and the calcium carbide are slowly released, and the water permeates an oil film on the surface of the calcium carbide and reacts with the water to foam;
along with the hydration of cement, the aluminum powder and the hydration product of the cement react to generate gas, an expansion space is formed in the slurry, and the slow-release foaming stability and uniformity are strong.
5. In order to increase the stability of the foam, a surfactant is added and is formed by compounding an anionic surfactant, namely fatty alcohol-polyoxyethylene ether sodium sulfate, and a nonionic surfactant, namely methyl glucoside polyoxyethylene ether dioleate (DOE-120), and a small amount of cationic surfactant, namely cetyl trimethyl ammonium bromide, is added, the electric property of the cationic surfactant is opposite to that of the anionic surfactant, but hydrophobic interaction exists on the carbon chain of macromolecules of the cationic surfactant, and the nonionic surfactant is inserted into the cationic surfactant, so that the interaction is stronger, micelles are formed more easily, and the surface tension of the foaming agent is further reduced; in addition, the surfactant has more functional groups, so that the viscosity of the bubble film can be increased, and the toughness and stability of the foam are increased; a small amount of nano calcium carbonate has large surface area, is adsorbed on the surface of the foam to increase the surface energy of the foam surface and increase the stability of the foam.
Drawings
FIG. 1 is a graph showing the results of the expansion test of the present invention.
Detailed Description
The invention is further described below with reference to specific embodiments.
Example 1
The coal mine filling material is prepared from the following raw materials in parts by weight: 20 parts of fly ash, 45 parts of 42.5 portland cement, 5 parts of construction waste, 18 parts of coal gangue, 2 parts of composite fiber, 3 parts of additive, 0.8 part of expanding agent, 5 parts of styrene-acrylic emulsion, 0.6 part of foam stabilizer and 100 parts of water.
The construction waste is subjected to activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and is kept warm for 60min.
The additive is prepared by the following steps:
(1) Crushing the dried straws, soaking the straws in 9% potassium hydroxide solution at 50 ℃ for 3h, wherein the solid-to-liquid ratio is 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw into the mixture, and reacting the mixture in a roomStirring for 30-40min under warm condition 2 Adding potassium persulfate at 70 ℃ under the atmosphere to initiate the reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuing to react for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, alkalized straw, sodium carboxymethylcellulose, hectorite, sodium dodecyl sulfate, N-methylene bisacrylamide, polyethylene glycol diacrylate, potassium persulfate to water is 36:9:1:2:3.5:0.3:0.025:0.02:0.35:100.
the expanding agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, mixing the mixture with a proper amount of absolute ethyl alcohol uniformly, adding calcium carbide, performing ultrasonic oscillation for 1 hour, and evaporating the absolute ethyl alcohol to obtain coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is 3:100;
(2) Soaking expanded vermiculite in 1.5mol/L hydrochloric acid for 24 hours, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the coated calcium carbide and the aluminum powder according to a weight ratio of 2:0.5:0.5 stirring evenly to obtain the expanding agent.
The composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and the length of the composite fiber is 5-6mm.
The foam stabilizer comprises the following components: 10 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 10 parts of methyl glucoside polyoxyethylene ether dioleate, 2 parts of hexadecyl trimethyl ammonium bromide and 2 parts of nano calcium carbonate.
A preparation process of a coal mine filling material comprises the following steps:
uniformly mixing the fly ash, the cement, the building waste and the coal gangue, adding the composite fiber, and further uniformly stirring; then adding the rest raw materials, uniformly stirring, and pressurizing and conveying to a region to be filled through a pipeline pump.
Example 2
The coal mine filling material is prepared from the following raw materials in parts by weight: 21 parts of fly ash, 44 parts of 42.5 Portland cement, 6 parts of construction waste, 17 parts of coal gangue, 2.5 parts of composite fiber, 3.5 parts of an additive, 0.9 part of an expanding agent, 5.2 parts of styrene-acrylic emulsion, 0.65 part of a foam stabilizer and 100 parts of water.
The construction waste is subjected to activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and is kept warm for 60min.
The additive is prepared by the following steps:
(1) Crushing the dried straws, soaking the straws in 9% potassium hydroxide solution at 50 ℃ for 3h, wherein the solid-to-liquid ratio is 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw, stirring for 30-40min at room temperature 2 Adding potassium persulfate at 70 ℃ under the atmosphere to initiate the reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuing to react for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of the acrylic acid, the 2-acrylamide-2-methylpropanesulfonic acid, the alkalized straw, the sodium carboxymethyl cellulose, the hectorite, the sodium dodecyl sulfate, the N, N-methylene bisacrylamide, the polyethylene glycol diacrylate, the potassium persulfate and the water is 36:9:1:2:3.8:0.3:0.025:0.02:0.35:100.
the expanding agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, uniformly mixing with a proper amount of absolute ethyl alcohol after mixing, then adding calcium carbide, carrying out ultrasonic oscillation for 1h, and evaporating the absolute ethyl alcohol to obtain film-coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is 3.5:100, respectively;
(2) Soaking expanded vermiculite in 1.5mol/L hydrochloric acid for 24 h, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the film-coated calcium carbide and aluminum powder according to a weight ratio of 2:0.5:0.6, stirring uniformly to obtain the expanding agent.
The composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and the length of the composite fiber is 5-6mm.
The foam stabilizer comprises the following components: 11 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 11 parts of methyl glucoside polyoxyethylene ether dioleate, 3 parts of hexadecyl trimethyl ammonium bromide and 2.5 parts of nano calcium carbonate.
The preparation process was the same as in example 1.
Example 3
The coal mine filling material is prepared from the following raw materials in parts by weight: 23 parts of fly ash, 42.5 parts of Portland cement, 7 parts of construction waste, 16 parts of coal gangue, 3 parts of composite fiber, 3.5 parts of additive, 1.0 part of expanding agent, 5.5 parts of styrene-acrylic emulsion, 0.65 part of foam stabilizer and 100 parts of water.
The construction waste is subjected to activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and is kept warm for 60min.
The additive is prepared by the following steps:
(1) Crushing dried straws, and soaking the straws in a 10% potassium hydroxide solution at 50 ℃ for 3 hours at a solid-to-liquid ratio of 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw, stirring for 30-40min at room temperature 2 Adding potassium persulfate into the atmosphere at 70 ℃ to initiate reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuously reacting for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of the acrylic acid, the 2-acrylamide-2-methylpropanesulfonic acid, the alkalized straw, the sodium carboxymethyl cellulose, the hectorite, the sodium dodecyl sulfate, the N, N-methylene bisacrylamide, the polyethylene glycol diacrylate, the potassium persulfate and the water is 36:9:1:2:4.0:0.3:0.025:0.02:0.35:100.
the expanding agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, uniformly mixing with a proper amount of absolute ethyl alcohol after mixing, then adding calcium carbide, carrying out ultrasonic oscillation for 1h, and evaporating the absolute ethyl alcohol to obtain film-coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is 3.5:100;
(2) Soaking expanded vermiculite in 2.0mol/L hydrochloric acid for 24 h, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the film-coated calcium carbide and aluminum powder according to a weight ratio of 2:0.5:0.8, stirring evenly to obtain the expanding agent.
The composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and the length of the composite fiber is 5-6mm.
The foam stabilizer is 12 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 12 parts of methyl glucoside polyoxyethylene ether dioleate, 4 parts of hexadecyl trimethyl ammonium bromide and 2.5 parts of nano calcium carbonate.
The preparation process was the same as in example 1.
Example 4
The coal mine filling material is prepared from the following raw materials in parts by weight: 25 parts of fly ash, 40 parts of 42.5 portland cement, 8 parts of construction waste, 15 parts of coal gangue, 2.5 parts of composite fiber, 4 parts of additive, 1.0 part of expanding agent, 6 parts of styrene-acrylic emulsion, 0.7 part of foam stabilizer and 100 parts of water.
The construction waste is subjected to activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and the temperature is kept for 60min.
The additive is prepared by the following steps:
(1) Crushing dried straws, and soaking the straws in a 10% potassium hydroxide solution at 50 ℃ for 3 hours at a solid-to-liquid ratio of 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw, stirring for 30-40min at room temperature 2 Adding potassium persulfate into the atmosphere at 70 ℃ to initiate reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuously reacting for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of the acrylic acid, the 2-acrylamide-2-methylpropanesulfonic acid, the alkalized straw, the sodium carboxymethyl cellulose, the hectorite, the sodium dodecyl sulfate, the N, N-methylene bisacrylamide, the polyethylene glycol diacrylate, the potassium persulfate and the water is 36:9:1:2:4.5:0.3:0.025:0.02:0.35:100.
the expanding agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, mixing the mixture with a proper amount of absolute ethyl alcohol uniformly, adding calcium carbide, performing ultrasonic oscillation for 1 hour, and evaporating the absolute ethyl alcohol to obtain coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is (4): 100, respectively;
(2) Soaking expanded vermiculite in 2mol/L hydrochloric acid for 24 h, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the film-coated calcium carbide and aluminum powder according to a weight ratio of 2:0.5:1, uniformly stirring to obtain the expanding agent.
The composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and the length of the composite fiber is 5-6mm.
The foam stabilizer is 15 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 15 parts of methyl glucoside polyoxyethylene ether dioleate, 5 parts of hexadecyl trimethyl ammonium bromide and 3 parts of nano calcium carbonate.
Comparative test
Comparative example 1
Comparative example 1 differs from example 4 in that: the step (1) of the preparation process of the admixture is not added with the polyethylene glycol diacrylate.
Comparative example 2
Comparative example 2 is based on example 4, and no additive is added to the raw materials of the coal mine filling material.
Comparative example 3
Comparative example 3 is based on example 4, and no expanding agent is added to the raw material of the coal mine filling material.
Comparative example 4
On the basis of example 4, the expanding agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, uniformly mixing with a proper amount of absolute ethyl alcohol after mixing, then adding calcium carbide, carrying out ultrasonic oscillation for 1h, and evaporating the absolute ethyl alcohol to obtain coated calcium carbide, wherein the weight ratio of oleic acid to coated calcium carbide is 4:100.
comparative example 5
Comparative example 5 no foam stabilizer was added to the coal mine filler material of example 4.
Performance detection
1. Expansion test of Admixture
The expansion property is mainly characterized by the water absorption expansion multiple within a certain time; the test method comprises the following steps: weighing a certain amount of gel particles (m) 1 ) Placing into a beaker, adding a certain amount of water, standing at a certain temperature for a certain time, taking out gel particles after water swelling, filtering with a filter screen, sucking excess water on the surface with filter paper, and weighing (m) 2 ). Water absorption expansion multiple = (m) 2 -m 1 ）/m 1 The water absorption capacity of the admixture to physiological saline was measured with 0.9% NaCl solution based on the complicated composition of the slurry in the present application, wherein the results of the test for the expansion capacity of the admixture prepared in examples 1 to 4 and comparative example 1 are shown in FIG. 1.
As can be seen from FIG. 1, the water absorption swelling capacity of the admixtures prepared in examples 1-4 is good, the balance is achieved at 50min of water absorption, and the physiological saline absorption multiple is 120-130g/g, and compared with comparative example 1, the water absorption swelling speed of comparative example 1 is higher than that of examples 1-4, and finally the water absorption multiple of the physiological saline is lower than that of example 4, which shows that the addition of the polyethylene glycol diacrylate can delay the previous water absorption swelling speed of the admixtures and can also increase the water absorption multiple of the physiological saline.
2. Properties of the Filler
The slurry fluidity test refers to the fluidity of GB/T8077-2012 cement paste; pouring the mixed slurry into a 70.7mm cube test block, placing in a constant temperature and humidity curing box 7d and 28d to test the compression strength and the bending strength; the swelling ratio of the filler was measured by pouring the mixed slurry into a 70.7mm test mold, leaving a 30mm space in between, curing for a period of time, measuring the distance of the test block from the upper edge of the mold and recording as a, the swelling ratio is = (30-a)/(70.7-30).
TABLE 1 Performance test
The data in the table 1 show that the slurry concentration of the slurry is 65%, the fluidity is good, the expansion rate of the filling body is 16-22%, the compressive strength is 3.4-4.8MPa, the expansion rate of the filling body is increased along with the increase of the expanding agent, and the growth rate is increased within 3 h; comparative example 2, in which no additive was added, shows that the expansion rate is lower than that of example 4, and the addition of the additive contributes to the expansion of the filler; in comparative example 3, no expanding agent was added, and the distance from the test block to the upper edge of the mold was not changed at a little time of curing; the swelling agent of comparative example 4, in which aluminum powder and expanded vermiculite were not added, exhibited a higher swelling rate within 1 hour than that of example 4, indicating that expanded vermiculite can exert a sustained release effect, and also exhibited a lower swelling rate than that of example 4 due to the absence of aluminum powder. Comparative example 5, in which no foam stabilizer was added, showed a significantly lower expansion than example 4, indicating that the foam stabilizer of the present application can improve the stability of the foam.
Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.
Claims (7)
1. A coal mine filling material is characterized in that: the feed is prepared from the following raw materials in parts by weight: 20-25 parts of fly ash, 40-45 parts of cement, 5-8 parts of construction waste, 15-18 parts of coal gangue, 2-3 parts of composite fiber, 3-4 parts of additive, 0.8-1.0 part of expanding agent, 5-6 parts of styrene-acrylic emulsion, 0.6-0.7 part of foam stabilizer and 100 parts of water.
2. The coal mine packing material of claim 1, wherein the construction waste is subjected to an activation pretreatment: the concrete waste is crushed and heated to 1400 ℃ at the speed of 5 ℃/min and is kept warm for 60min.
3. The coal mine filling material as claimed in claim 1, wherein the admixture is prepared by the following steps:
(1) Crushing the dried straws, soaking for 3 hours at 50 ℃ by adopting 9-10% alkali liquor by mass percent, wherein the solid-liquid ratio is 1:5, filtering, washing to be neutral and drying to obtain alkalized straw;
(2) Adding sodium carboxymethylcellulose into water, and stirring at 80 deg.C for 30-40min; then adding 2-acrylamide-2-methylpropanesulfonic acid, hectorite, N-methylene bisacrylamide, polyethylene glycol diacrylate, sodium dodecyl sulfate and alkalized straw, stirring for 30-40min at room temperature 2 Adding potassium persulfate at 70 ℃ under the atmosphere to initiate the reaction for 5min;
(3) Adding acrylic acid into alkali liquor to adjust the neutralization degree to 85%, adding the acrylic acid into the mixed liquor, continuing to react for 2.5 hours, then soaking and washing the acrylic acid with ethanol, drying and crushing the acrylic acid to obtain a product;
the weight ratio of the acrylic acid, the 2-acrylamide-2-methylpropanesulfonic acid, the alkalized straw, the sodium carboxymethyl cellulose, the hectorite, the sodium dodecyl sulfate, the N, N-methylene bisacrylamide, the polyethylene glycol diacrylate, the potassium persulfate and the water is 36:9:1:2:3.5-4.5:0.3:0.025:0.015:0.35:100.
4. the coal mine filling material as claimed in claim 1, wherein the swelling agent is prepared by the following method:
(1) Oleic acid and hydrogenated castor oil in a weight ratio of 1:1, mixing the mixture with a proper amount of absolute ethyl alcohol uniformly, adding calcium carbide, performing ultrasonic oscillation for 1 hour, and evaporating the absolute ethyl alcohol to obtain coated calcium carbide, wherein the weight ratio of oleic acid to calcium carbide is (3-4): 100, respectively;
(2) Soaking expanded vermiculite in 1.5-2 mol/L hydrochloric acid for 24 h, wherein the solid-liquid ratio is 1:2, washing and drying, and mixing with the coated calcium carbide and the aluminum powder according to a weight ratio of 2:0.5:0.5 to 1 portion of the mixture is evenly stirred to obtain the expanding agent.
5. The coal mine filling material as claimed in claim 1, wherein the composite fiber is a mixed fiber of straw fiber and polypropylene fiber, and has a length of 5-6mm.
6. The coal mine filling material as claimed in claim 1, wherein the foam stabilizer has the following composition: 10-15 parts of fatty alcohol-polyoxyethylene ether sodium sulfate, 10-15 parts of methyl glucoside polyoxyethylene ether dioleate, 2-5 parts of hexadecyl trimethyl ammonium bromide and 2-3 parts of nano calcium carbonate.
7. A process for preparing the coal mine filling material of claim 1, which is prepared by the following steps:
uniformly mixing the fly ash, the cement, the building waste and the coal gangue, adding the composite fiber, and further uniformly stirring; then adding the rest raw materials, stirring uniformly, and conveying to the area to be filled by pressurizing through a pipeline pump.
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| CN202211668691.3A CN115745526A (en) | 2022-12-24 | 2022-12-24 | Coal mine filling material and preparation process thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116444287A (en) * | 2023-04-19 | 2023-07-18 | 国发环保新材料(江门)有限公司 | Foamed ceramic production process and equipment |
| CN118084411A (en) * | 2024-02-29 | 2024-05-28 | 中国矿业大学 | Coal mine paste filling material with energy absorption, bearing and cooling characteristics and preparation method thereof |
-
2022
- 2022-12-24 CN CN202211668691.3A patent/CN115745526A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116444287A (en) * | 2023-04-19 | 2023-07-18 | 国发环保新材料(江门)有限公司 | Foamed ceramic production process and equipment |
| CN116444287B (en) * | 2023-04-19 | 2024-05-07 | 国发环保新材料(江门)有限公司 | Foamed ceramic production process and equipment |
| CN118084411A (en) * | 2024-02-29 | 2024-05-28 | 中国矿业大学 | Coal mine paste filling material with energy absorption, bearing and cooling characteristics and preparation method thereof |
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